The Dynamic EarthSection 2 Objectives Diagram the % composition of Earth’s atmospheric gasses. Label the layers of Earth’s atmosphere. Identify three mechanisms of heat transfer in Earth’s atmosphere. Explain the greenhouse effect.

The Dynamic EarthSection 2 The Atmosphere The atmosphere is a mixture of gases that surrounds a planet, such as Earth. Nitrogen, oxygen, carbon dioxide, and other gases are all parts of this mixture. Gases can be added to and removed from the atmosphere through living organisms. For example, animals remove oxygen when they breathe in and add carbon dioxide when they breath out.

The Dynamic EarthSection 2 Composition of the Atmosphere In addition to nitrogen and oxygen, other gases such as argon, carbon dioxide, methane, and water vapor make up the rest of the atmosphere. Label the pie chart with the correct gasses by percentage. 78% 21% 1%

The Dynamic EarthSection 2 Air Pressure Almost the entire mass of Earth’s atmospheric gases is located within 18.6 miles of the surface. Earth’s atmosphere is pulled toward Earth’s surface by gravity and as a result, the atmosphere is denser near the Earth’s surface. –Why is breathing at higher elevations is more difficult?

The Dynamic EarthSection 2 Layers of the Atmosphere

The Dynamic EarthSection 2 Energy Transfer in the Atmosphere Define –Radiation=sun –Conduction=contact –Convection=mixing

The Dynamic EarthSection 2 Warming of the Atmosphere Solar energy reaches Earth as electromagnetic radiation, which includes visible light, infrared radiation, and ultraviolet light.

The Dynamic EarthSection 2 Warming of the Atmosphere Earth does not continue to get warmer because the oceans and the land radiate the absorbed energy back into the atmosphere. Dark-colored objects absorb more solar radiation that light- colored objects, so dark colored objects have more energy to release as heat. –What does this mean in the Arctic? –How does this help explain why the temperature in cities is higher than the temperature in the country?

The Dynamic EarthSection 2 The Movement of Energy in the Atmosphere As a current of air, warmed by Earth’s surface, rises into the atmosphere, it begins to cool, and eventually becomes more dense than the air around it and sinks. This current then moves back toward Earth until heated and less dense and then begins to rise again. The continual process of warm air rising and cool air sinking and moving air in a circular motion is called a convection current. These convection currents drive global weather patterns!

The Dynamic EarthSection 2 The Greenhouse Effect The greenhouse effect is the warming of the surface and lower atmosphere of Earth that occurs when water vapor, carbon dioxide, methane, and nitrous oxide in the air absorb and reradiate infrared radiation. –Greenhouse gasses occur naturally and as a result of human activity –Without the greenhouse effect, Earth would be too cold for life to exist…go to far …GLOBAL WARMING! –This explains why your car is hot inside on a warm day.